The discovery of constitutive activating mutations in the proto-oncogene receptor tyrosine kinase (KIT) or platelet-derived growth factor receptor α (PDGFRA) oncogenes as molecular drivers of most gastrointestinal stromal tumors (GISTs) [1,2] has radically changed our knowledge on their tumor biology. The gene discussed is PDGFRA; the disease is gastrointestinal stromal tumor.